Respiratory System Clinical Signs - Pathology

Bilateral discharge:
- Lesion is caudal to nasal septum eg: pharyngeal lesion; LRT lesion in horses
- Lesion has resulted in nasal septum destruction
  - Neoplasia
  - Fungal infection
Unilateral discharge:
- Lesion is cranial to nasal septum eg: nasal or sinus lesion; pharyngeal or guttural pouch lesion in horses.
Type of discharge
- Serous
- Catarrhal
- Purrulent
- Haemorrhage

Haemorrhage from the nose
May originate from nasopharynx or lower respiratory tract
Causes
- Inflammation eg: ulcerative rhinitis
- Neoplasia eg: infiltrating tumour, haemangioma
- Trauma
- Clotting defects

Horse:
- Nasal aspergillosis
- Ethmoidal haematoma = 'Haemorrhagic nasal polyp', 'Progressive haematoma' - arise from the ethmoid region and can extend to fill the nasal cavity. They can be difficult to control as they can recur after surgery.
  - Histology - multiple areas of acute to chronic haemorrhage within a fibrous tissue stroma.
- Exercise-induced pulmonary haemorrhage
- Rupture of rectus capitus - profuse haemorrhage
- Mycotic infection of guttural pouches
- Nasolacrimal haemorrhage
- Nasal/pharyngeal trauma/foreign body
- Sinus neoplasia
- Sinus cyst
- Sinusitis
- Lower airway disease
- Pulmonary neoplasia
- Cardiac
  - Mitral insufficiency
  - Atrial fibrillation
- Skeletal
  - Head trauma
- Rarely hypertension or vascular aneurysms

Blood stained nose at post-mortem - terminal pulmonary congestion, oedema, haemorrhage

Equine respiratory disease by clinical signs
- Contains pictures and videos
- From Equine Respiratory Diseases edited by P. Lekeux, published by the International Veterinary Information Service (IVIS)
- Requires IVIS membership